Radiofrequency Echographic Multi-Spectrometry (REMS) and Dual-Energy X-rays Absorptiometry for the Evaluation of Bone Mineral Density in a Peritoneal Dialysis Setting

Background Radiofrequency echographic multi-spectrometry (REMS) is a novel ultrasound-based technique that has shown good reliability in the assessment of bone mineral density (BMD). Objectives The aim of this study was to compare the performance of the REMS BMD assessment with dual-energy X-rays absorptiometry (DXA) in a cohort of patients affected by end-stage renal disease undergoing peritoneal dialysis (PD). Methods Consecutive patients referring to the PD clinic of our hospital were enrolled. Lumbar spine and proximal femur REMS scans were performed, and lumbar spine (anteroposterior and laterolateral) and proximal femur DXA scans were performed as well. Clinical data were extracted from medical records. The risk assessment outputs of two fracture risk algorithms (FRAX and DeFRA), calculated upon the worst BMD obtained from either technique were compared as well. Analysis of variance (ANOVA) with post hoc analysis (Bonferroni) and a two-sided Student’s t-test were used to estimate the absolute differences between groups. Written informed consent was obtained from all participants included (protocol 1483 CESC). Results 41 total patients were enrolled (Table 1). No significant differences were documented between the BMD T-scores measured through DXA or REMS at the proximal femur. At the lumbar spine, the DXA laterolateral T-score was not significantly different from that of REMS, while the DXA anteroposterior T-score was significantly higher than both the anteroposterior DXA and the REMS measurements (Figure 1, panel A and B). When either DXA or REMS was adopted, no significant difference in the fracture risk estimate was found for both algorithms (Figure 1, panel C and D). Table 1. anthropometrics, clinical and biochemical characteristics of the enrolled sample. CKD, chronic kidney disease; PTH, parathyroid hormone; ALP, alkaline phosphatase; IQR, interquartile range; VFA, vertebral fracture assessment. Sample size (M) 41 (29) Age (y) Median [IQR] 62 [52-73] Height (cm) Median [IQR] 170 [165-176] Body weight (Kg) Median [IQR] 74 [61-83] Body mass index (Kg/m2) Median [IQR] 25 [22-27.8] Disease duration – CKD (months) Median [IQR] 132 [48-140] Dialysis duration (months) Median [IQR] 10 [3-24] S-calcium (mg/dL) Median [IQR] 9.1 [8.6-9.4] S-phosphorous (mg/dL) Median [IQR] 5.4 [4.6-6.4] PTH (pg/mL) Median [IQR] 31.4 [22.8-46.8] 25OH Vitamin D (nmol/L) Median [IQR] 53 [36-72] Patients with morphometric fractures (VFA) 15% Patients with femoral fractures 2.4% Total n° of morphometric fractures 12 Figure 1. comparison of the mean T-scores (error bars represent 95%CI) measured with DXA and REMS at the lumbar spine (panel A), and at the femur (panel B). Comparison between the DeFRA DXA and REMS-derived outputs (panel C) and FRAX DXA and REMS-derived outputs (panel D) raw and after correction for TBS. DeFRA, FRAX-derived risk assessment tool; FRAX, Fracture Risk Assessment tool; AP, anteroposterior; LL, latero-lateral; TH, total hip; FN, femoral neck; TBS, trabecular bone score. Conclusion Our data showed a good agreement, in a real-life PD setting, between the DXA and REMS-derived BMDs and in the consequent fracture risk assessment obtained with the FRAX or DeFRA tools. Disclosure of Interests Angelo Fassio: None declared, Stefano Andreola: None declared, Davide Gatti Paid instructor for: Amgen, Celgene Eli-Lilly, MSD-Italia, Organon, UCB., Consultant of: Amgen, Celgene Eli-Lilly, MSD-Italia, Organon, UCB., Matteo Gatti: None declared, Giovanni Gambaro Speakers bureau: Vifor Pharma, Maurizio Rossini Speakers bureau: Abiogen, Amgen, Abbvie, BMS, Celgene, Eli-Lilly, Galapagos, Grunenthal, MSD, Novartis, Pfizer, Sanofi, Sandoz, Theramex, UCB., Ombretta Viapiana: None declared, Giulia Zanetti: None declared, Francesca Pistillo: None declared, Valeri Messina: None declared, Giovanni Adami: None declared